U.S. patent application number 13/356713 was filed with the patent office on 2013-07-25 for stairway assembly for a machine.
This patent application is currently assigned to Caterpillar Inc.. The applicant listed for this patent is Vijay Venkataraman. Invention is credited to Vijay Venkataraman.
Application Number | 20130187354 13/356713 |
Document ID | / |
Family ID | 48796595 |
Filed Date | 2013-07-25 |
United States Patent
Application |
20130187354 |
Kind Code |
A1 |
Venkataraman; Vijay |
July 25, 2013 |
STAIRWAY ASSEMBLY FOR A MACHINE
Abstract
A stairway having a first section hingedly connected to the
platform by a first pin joint. The first section is connected to
the platform at a proximal end. The first pin joint allows for a
rotation of the first section about a first hinge axis. Further, a
second section is hingedly connected to the first section by a
second pin joint. The second section is connected at a distal end
of the first section. The second pin joint allows for a rotation of
the second section about a second hinge axis. An actuator is
pivotally connected to the platform by a first joint and to the
distal end of the first section by a second joint.
Inventors: |
Venkataraman; Vijay;
(Chennai, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Venkataraman; Vijay |
Chennai |
|
IN |
|
|
Assignee: |
Caterpillar Inc.
Peoria
IL
|
Family ID: |
48796595 |
Appl. No.: |
13/356713 |
Filed: |
January 24, 2012 |
Current U.S.
Class: |
280/166 |
Current CPC
Class: |
B60R 3/005 20130101 |
Class at
Publication: |
280/166 |
International
Class: |
B60R 3/00 20060101
B60R003/00 |
Claims
1. A stairway for a platform, the stairway comprising: a first
section hingedly connected to the platform by a first pin joint at
a proximal end of the first section, the first pin joint allows a
rotation of the first section about a first hinge axis; a second
section hingedly connected to the first section by a second pin
joint at a distal end of the first section, the second pin joint
allows a rotation of the second section about a second hinge axis;
and an actuator pivotally connected to the platform by a first
joint and to the distal end of the first section by a second
joint.
2. The stairway of claim 1, wherein the actuator includes a
cylinder and a piston disposed in the cylinder.
3. The stairway of claim 2, wherein the piston is adapted to extend
and contract in the cylinder to raise and lower the distal end of
the first section with respect to the platform.
4. The stairway of claim 1, wherein the actuator is a linear
hydraulic motor.
5. The stairway of claim 1 further including a pushrod, wherein the
pushrod is pivotally connected to the platform at a first end and
to the second section at a second end.
6. The stairway of claim 5, wherein the pushrod is configured to
provide a constrained movement of the second section with respect
to the first section between an operating state and a folded
state.
7. The stairway of claim 1, wherein the first section includes a
first pair of side plates with a plurality of steps disposed
therebetween.
8. The stairway of claim 1, wherein the second section includes a
second pair of side plates with a plurality of steps disposed
therebetween.
9. The stairway of claim 1 further including a first pair of side
rails and a second pair of side rails, wherein the first pair of
side rails and the second pair of side rails are disposed on the
first section and the second section respectively.
10. A stairway assembly adapted to be used in a machine with a
platform elevated from a ground, the stairway assembly comprising:
a controller in connection with an operator switch, the controller
is configured to generate an operator signal on activation of the
operator switch; a hydraulic circuit configured to supply a
hydraulic fluid based on the operator signal; and a stairway
mounted to the platform, the stairway including: a first section
hingedly connected to the platform by a first pin joint at a
proximal end of the first section, a second section hingedly
connected to the first section by a second pin joint at a distal
end of the first section, an actuator pivotally connected to the
platform by a first joint and to the distal end of the first
section by a second joint, the actuator is in fluid communication
with the hydraulic circuit to receive the hydraulic fluid, and a
pushrod pivotally connected to the platform at a first end and to
the second section at a second end.
11. The stairway assembly of claim 10, wherein the pushrod is
configured to provide a constrained movement of the second section
with respect to the first section between an operating state and a
folded state of the stairway.
12. The stairway assembly of claim 10 further including one or more
sensors in connection with the controller to determine whether the
stairway is in an operating state or a folded state.
13. The stairway assembly of claim 10, wherein the hydraulic
circuit includes a pump to pressurize the hydraulic fluid and a
control valve to supply the hydraulic fluid based at least in part
on the operator signal.
14. The stairway assembly of claim 10, wherein the actuator
includes a cylinder and a piston disposed in the cylinder.
15. The stairway assembly of claim 14, wherein the piston is
adapted to extend and contract in the cylinder based on the supply
of the hydraulic fluid, so as to raise and lower the distal end of
the first section with respect to the platform.
16. A machine comprising: an operator station disposed at an
elevation from a ground, the operator station being accessible via
a platform; and a stairway mounted to the platform, the stairway
including: a first section hingedly connected to the platform by a
first pin joint at a proximal end of the first section, a second
section hingedly connected to the first section by a second pin
joint at a distal end of the first section, an actuator pivotally
connected to the platform by a first joint and to the distal end of
the first section by a second joint, and a pushrod pivotally
connected to the platform at a first end and to the second section
at a second end.
17. The machine of claim 16, wherein the pushrod is configured to
provide a constrained movement of the second section with respect
to the first section between an operating state and a folded state
of the stairway.
18. The machine of claim 16 further including a control unit, the
control unit including: a controller in connection with an operator
switch, the controller is configured to generate an operator signal
on activation of the operator switch; and a hydraulic circuit
including a pump to pump a hydraulic fluid and a control valve to
supply a hydraulic fluid to the actuator based at least in part on
the operator signal.
19. The machine of claim 18 further including one or more sensors
in connection with the controller to determine whether the stairway
is in an operating state or a folded state.
20. The machine of claim 18, wherein the actuator includes a
cylinder and a piston adapted to extend or contract in the cylinder
based on the supply of the hydraulic fluid, so as to raise or lower
the distal end of the first section with respect to the platform.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a stairway assembly for a
machine and more particularly to a stairway configured to be
folded.
BACKGROUND
[0002] Large machines, such as a power shovel used in construction
and mining applications generally have an operator station
positioned at an elevation from the ground. The operator station
may include means to control the various functions of the machine.
The operator may access the operator station by climbing a
stairway, which is typically disposed adjacent to the operator
station. The stairway may be provided along a lateral side of the
machine. During operation, some of the vibrations induced in the
machine may be transmitted to the stairway. This may cause the
stairway to collide and bounce of the side of the machine and cause
some damage.
[0003] Published patent application JP2009263876A discloses a
stairway assembly for a machine. The stairway assembly includes a
hydraulic mechanism to lift or lower a foldable stairway. The
stairway assembly also includes a locking mechanism operatively
connected to the hydraulic mechanism to move a lock lever
associated with the locking mechanism to a release position during
operation.
SUMMARY
[0004] In one aspect, the present disclosure provides a stairway
for a platform. The stairway includes a first section hingedly
connected to the platform by a first pin joint. The first section
is connected to the platform at a proximal end of the first
section. The first pin joint allows for a rotation of the first
section about a first hinge axis. Further, a second section is
hingedly connected to the first section by a second pin joint. The
second section is connected at a distal end of the first section.
The second pin joint allows for a rotation of the second section
about a second hinge axis. An actuator is pivotally connected to
the platform by a first joint and to the distal end of the first
section by a second joint.
[0005] In another aspect, the present disclosure provides a
stairway assembly adapted to be used in a machine with the platform
elevated from a ground. The stairway assembly includes a controller
in connection with an operator switch. The controller is configured
to generate an operator signal on activation of the operator
switch. Further, a hydraulic circuit is provided to supply a
hydraulic fluid based on the operator signal. The stairway assembly
further includes the stairway. The stairway includes the first
section hingedly connected to the platform by the first pin joint.
The first section is connected to the platform at the proximal end
of the first section. The first pin joint allows for the rotation
of the first section about the first hinge axis. Further, the
second section is hingedly connected to the first section by the
second pin joint. The second section is connected at the distal end
of the first section. The second pin joint allows for the rotation
of the second section about the second hinge axis. An actuator is
pivotally connected to the platform by the first joint and to the
distal end of the first section by the second joint. The actuator
is in fluid communication with the hydraulic circuit to receive the
hydraulic fluid. Further, the pushrod is pivotally connected to the
platform at the first end and to the second section at the second
end.
[0006] In yet another aspect, the present disclosure provides a
machine. The machine includes an operator station disposed at an
elevation from the ground, the operator station being accessible
via the platform. The machine also includes the stairway mounted to
the platform. The stairway includes the first section hingedly
connected to the platform by the first pin joint. The first section
is connected to the platform at the proximal end of the first
section. The first pin joint allows for the rotation of the first
section about the first hinge axis. Further, the second section is
hingedly connected to the first section by the second pin joint.
The second section is connected at the distal end of the first
section. The second pin joint allows for the rotation of the second
section about the second hinge axis. An actuator is pivotally
connected to the platform by the first joint and to the distal end
of the first section by the second joint. Further, the pushrod is
pivotally connected to the platform at a first end and to the
second section at a second end. The pushrod is configured to
provide a constrained movement of the second section with respect
to the first section between an operating state and a folded state
of the stairway.
[0007] Other features and aspects of this disclosure will be
apparent from the following description and the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 illustrates a perspective view of a machine;
[0009] FIG. 2 illustrates a side view of the machine of FIG. 1;
[0010] FIG. 3 illustrates a perspective view of a stairway;
[0011] FIG. 4 illustrates a side view of the stairway of FIG. 3 in
an operating state;
[0012] FIG. 5 illustrates a side view of the stairway of FIG. 3 in
a folded state;
[0013] FIG. 6 illustrates a block diagram for a stairway assembly;
and
[0014] FIG. 7 illustrates a side view of the stairway of FIG. 3 in
an interim state.
DETAILED DESCRIPTION
[0015] The present disclosure will now be described in detail with
reference being made to accompanying figures. A machine 100 in
which disclosed embodiments may be implemented is illustrated in
FIGS. 1-2. The machine 100 may be generically described as any
machine having an operator station positioned at an elevation from
ground. In the illustrated embodiment, the machine 100 is a mining
shovel. However, the machine 100 may be any machine used in
industries like mining or construction, for example, a wheel
loader, an excavator, a motor grader, a cold planer, a backhoe
loader, a track type tractor, a dump truck, a diesel locomotive or
the like. The machine 100 of the present disclosure may have
dimensions depending on various factors, such as, application,
type, etc.
[0016] The machine 100 includes a power source 102 for driving
various components in the machine 100. The power source 102 may be
an internal combustion engine such as petrol engine or a diesel
engine, an electrical source like a series of batteries, an
overhead conductor or the like. The machine 100 includes tracks 104
as ground engaging members to propel and maneuver the machine 100.
Alternatively, the machine 100 may use a set of drive wheels as the
ground engaging members. The machine 100 may further include a
chassis 106 to support various components of the machine 100.
Further, the machine 100 may include a linkage arm 108 supported on
the chassis 106 from one end and a bucket 110 disposed at other end
of the linkage arm 108.
[0017] The machine 100 may further include an operator station 112.
The operator station 112 may be defined in the form of an enclosure
and supported on the chassis 106. An operator may control the
various functions of the machine 100 through the operator station
112 by issuing commands using controls means, such as joysticks,
levers, touch based user interfaces, etc. provided in the operator
station 112. The operator station 112 may be accessible through a
platform 114 in the machine 100. As illustrated, the machine 100 of
the present disclosure may include a sidewalk 116 adjacent to the
operator station 112 which is reachable via the platform 114 by an
auxiliary stairway 118.
[0018] The platform 114 may be disposed at an elevation from a
ground 119. In an exemplary configuration, the platform 114 may be
at an elevation in the range of about 2-4 meters from the ground
119. To provide the operator with means to reach the operator
station 112, the machine 100 includes a stairway assembly 120. The
stairway assembly 120 includes a stairway 200 positioned along any
lateral side in the machine 100. The stairway 200 may be adapted to
be used by the operator to access the operator station 112. The
operator may ascend to the operator station 112 by climbing the
stairway 200 to reach the platform 114 and further the auxiliary
stairway 118 and walking down the sidewalk 116. The stairway 200 of
the present disclosure may be configured to be put in either an
operating state or a folded state.
[0019] In the accompanied drawings, FIG. 3 illustrates a
perspective view of the stairway 200. Further, FIG. 4 and FIG. 5
illustrate side views of the stairway 200 in the operating state
and the folded state respectively. The stairway 200 may be divided
into a plurality of sections, so as to put the stairway 200 from
the operating state to the folded state. For the purpose of the
present disclosure, the stairway 200 may include a first section
302 and a second section 304. In an exemplary configuration, the
first section 302 and the second section 304 may each have a length
in the range of about 1.5-2.5 meters. However, it will be apparent
to a person skilled in the art that the length of the first section
302 and the second section 304 may vary depending on the size of
the machine 100.
[0020] The first section 302 may be hingedly connected to the
platform 114 from a proximal end 306 of the first section 302. The
first section 302 may be connected to the platform 114 by a first
pin joint 308. The first pin joint 308 defines a first hinge axis
XX' for rotation of the first section 302 with respect to the
platform 114. Similarly, the second section 304 may be hingedly
connected to a distal end 310 of the first section 302. The second
section 304 may be connected to the first section 302 by a second
pin joint 312. The second pin joint 312 defines a second hinge axis
YY' for relative rotation of the second section 304 with respect to
the first section 302.
[0021] The first section 302 and the second section 304 may include
a first pair of side plates 314 and a second pair of side plates
316, respectively. The stairway 200 may also include a plurality of
steps 318 disposed between the first pair of side plates 314 and
the second pair of side plates 316. The plurality of steps 318 may
be spaced lengthwise in the stairway 200. Further, the stairway 200
may include a first pair of side rails 320 affixed to and extending
along the length of the first section 302 and a second pair of side
rails 322 affixed to and extending along the length of the second
section 304.
[0022] Further, the stairway 200 may include a pushrod 324 to
provide a connection between the platform 114 and the second
section 304. In an embodiment, the stairway 200 may include two
pushrods 324 disposed along each side. The pushrod 324 may be
pivotally connected to the platform 114 at a first end 326 and
pivotally connected to the second section 304 at a second end 328.
The pushrod 324 may be connected from both the first end 326 and
the second end 328 by means of pin joints. As illustrated, the
second end 328 may be located in the second section 304 near the
second pin joint 312 of the first section 302. In an exemplary
configuration, the pushrod 324 may have a length in the range of
about 1.5-2.5 meters.
[0023] Referring to FIGS. 4-5, the stairway 200 may also include an
actuator 400 disposed between the platform 114 and the first
section 302. The actuator 400 may act as a hydraulic link in the
stairway 200. The actuator 400 may include a cylinder 402 and a
piston 404. The piston 404 may be configured to move linearly,
extend and refract, in the cylinder 402 of the actuator 400.
Alternatively, the actuator 400 may be a linear hydraulic motor
having an extendable rod moving linearly on being actuated. In an
exemplary configuration, the piston 404 may extend and retract in a
range varying from 1-2.5 meters.
[0024] The actuator 400 may be pivotally connected to the platform
114 at a first joint 406 and pivotally connected to the first
section 302 at a second joint 408 of the stairway 200. The first
joint 406 and the second joint 408 may also be pin joints disposed
in the stairway 200. Specifically, the cylinder 402 of the actuator
400 may be pivotally connected to the platform 114 and the piston
404 of the actuator 400 may be pivotally connected to the distal
end 310 of the first section 302. The extension or retraction of
the piston 404 may result in raising or lowering of the distal end
310 and provide rotation of the first section 302 about the first
hinge axis XX' with respect to the platform 114.
[0025] The stairway 200 may also include a locking arrangement (not
illustrated) for holding the stairway 200 in the operating state.
The locking arrangement may also include the provision to adjust
the inclination angle of the second section 304 with respect to the
first section 302. The locking arrangement may be a mechanical
stopper having one face resting on the platform 114 and another
face bolted to the first section 302 of the stairway 200. Further,
a clamping arrangement (not illustrated) may be provided to
maintain the stairway 200 in the folded state. The clamping
arrangement may fasten the first section 302 or the second section
304 against the platform 114. Further, the clamping arrangement may
be used to lock the second section 304 against the first section
302, when the stairway 200 is in a folded state.
[0026] Moving on, FIG. 6 illustrates a schematic for the stairway
assembly 120 of the present disclosure. The stairway assembly 120
may include the stairway 200 and a control unit 602. As
illustrated, the control unit 602 may include an operator switch
604, which may be in the form of lever, push button, etc. disposed
in the machine 100. The operator switch 604 may be positioned in
the operator station 112 or so as to be accessible by the operator
from the ground 116. Alternatively, the operator switch 604 may be
in the form of a remote control operated by the operator.
[0027] The control unit 602 may further include a controller 606 to
generate an operator signal, when the operator switch 604 is
activated. The controller 606 may be a combination of, but not
limited to, a set of instructions, a Random Access Memory (RAM), a
Read Only Memory (ROM), flash memory, a data structure, and the
like. The controller 606 may further be configured to detect
whether the stairway 200 is in the operating state or the folded
state. This may be achieved by means of one or more sensors 608
associated with the stairway 200.
[0028] Further, the control unit 602 may include a hydraulic
circuit 610. The hydraulic circuit 610 may include a pump 612
providing a supply of hydraulic fluid. For the purpose of the
present disclosure, the pump 612 may be an electric motor pump
drawing power from battery in the machine 100. Alternatively, the
pump 612 may be a variable displacement hydraulic pump. The
hydraulic circuit 610 may further include a control valve 614
disposed in connection with the controller 606. The control valve
614 may be arranged to receive the operator signal from the
controller 606. The control valve 614 may control the supply of the
hydraulic fluid based at least in part on the operator signal.
[0029] The hydraulic fluid from the control valve 614 may be
supplied to the actuator 400. The piston 404 may move in the
cylinder 402 based on the received supply of the hydraulic fluid in
the actuator 400. In the actuator 400, the cylinder 402 may be
divided into a first side 616 and a second side 618, on either side
of the piston 404 in the cylinder 402. The piston 404 may extend in
the cylinder 402, when the hydraulic fluid is received in the first
side 616 of the cylinder 402. Conversely, when the hydraulic fluid
is received in the second side 618, the piston 404 may retract in
the cylinder 402.
INDUSTRIAL APPLICABILITY
[0030] The present disclosure is applicable to machines, for
example, a power shovel, such as a mining shovel, which are
commonly used in mines, construction sites and quarries. Typically,
these machines have high payload capabilities and therefore are
required to have large size. Due to the large size of such machines
and for the reason to provide a good field of view, the operator
station in such machines may generally be positioned at a high
elevation from the ground. The operator station may be accessible
by an operator via a stairway disposed in the machine.
[0031] The stairway may typically be provided along a lateral side
of the machine. The stairway may extend from one of the sides and
take up some of the installation space in the machine. During
operation of the machine, due to the vibrations induced by the
power source or the operating conditions, the stairway may vibrate
along with the chassis of the machine. This may cause the stairway
to strike the lateral sides of the machine to which the stairway is
installed and lead to some damage.
[0032] To minimize such problems, the stairway 200 of the present
disclosure is configured to be switched from the operating state to
the folded state. The stairway assembly 120 enables the operator to
switch the stairway 200 from the operating state to the folded
state and vice versa, as required. This way, the operator may put
the stairway 200 to the operating state, when need to reach the
operator station 112 and to the folded state, when not in use.
During operation, as the stairway 200 may be put to the folded
state. This reduces the space taken up by the stairway 200 in the
machine 100.
[0033] The operator may put the stairway 200 in either the
operating state or the folded state by activating the operator
switch 604 in the stairway assembly 120. The controller 606 may
determine whether the stairway is already in the operating state or
the folded state. Further, the controller 606 may generate the
operator signal to put the stairway 200 in the folded state, if the
stairway 200 is already in the operating state or vice versa.
[0034] In particular, when the controller 606 determines that the
stairway 200 is in the operating state, the operator switch 604
generates the operator signal to put the stairway 200 to the folded
state. The operator signal may instruct the control valve 614 to
pass the pressurized hydraulic fluid from the pump 612 to the first
side 616 in the cylinder 402 of the actuator 400. The hydraulic
fluid received in the first side 616 may cause the piston 404 to
extend in a direction away from the inside of the cylinder 402.
Subsequently, the linear motion of the piston 404 may be translated
to the rotational motion of the distal end 310 of the first section
302 about the first hinge axis XX'.
[0035] Due to the hinged coupling of the first section 302 with the
second section 304 about the second pin joint 312, the rotational
movement of the first section 302 may impart rotational movement to
the second section 304 about the second hinge axis YY'. This
movement of the second section 304 may be constrained by the
pushrod 324 in the stairway 200, causing the second section 304
move with the first section 302 from the substantially inclined
position to the vertical position. Finally, the second section 304
may abut with the first section 302, ultimately putting the
stairway 200 in the folded state as illustrated in FIG. 4.
[0036] Conversely, when the controller 606 determines the stairway
200 to be in the folded state, the operator switch 604 generates
the operator signal to put the stairway 200 to the operating state.
The operator signal may instruct the control valve 614 to allow the
hydraulic fluid to flow from the pump 612 to the second side 618 in
the cylinder 402 of the actuator 400. This makes the piston 404 to
retract inside the cylinder 402, causing the distal end 310 to
rotate about the second hinge axis YY'. Further, the second section
304 may move with the first section 302 from the substantially
vertical position to the inclined position due to constrained
movement provided by the pushrod 324 and ultimately putting the
stairway 200 in the operating state as illustrated in FIG. 5.
[0037] It is characteristic that the stairway 200 may fold or
unfold in a zigzag fashion by rotating about adjacent hinged axes
XX' and YY' of rotation in opposite directions. FIG. 7 illustrates
the stairway 200 in any one of an intermediate state between the
operating state and the folded state. Further, the rotational
movement of the stairway 200 is depicted by RR'. The stairway 200
moves in the direction R-R', when switched from the folded state to
the operating state and moves in the direction R'-R, when switched
from the operating state to the folded state. The locking
arrangement and the clamping arrangement may relieve the hydraulic
circuit 610 to provide a constant supply of the hydraulic fluid to
maintain the stairway 200 in the operating state or the folded
state.
[0038] Further, in an embodiment, the actuator 400 may provide some
dampening effect for the vibrations transmitted from the platform
114, connected to the chassis 106 in the machine 100, to the
stairway 200. These vibrations may be passed from the actuator 400
to the hydraulic circuit 610 by the hydraulic fluid. The hydraulic
circuit 610 may absorb some vibrations through an accumulator (not
illustrated). Thus, the stairway assembly 120 of the present
disclosure may also help to minimize the issue of vibrations in the
stairway 200 to some extent.
[0039] Although the embodiments of this disclosure as described
herein may be incorporated without departing from the scope of the
following claims, it will be apparent to those skilled in the art
that various modifications and variations can be made. Other
embodiments will be apparent to those skilled in the art from
consideration of the specification and practice of the disclosure.
It is intended that the specification and examples be considered as
exemplary only, with a true scope being indicated by the following
claims and their equivalents.
* * * * *